Color Measuring And Matching Of Colored Fiber Blends Containing Fluorescent Dyes

Colored spun yarn containing fluorescent dyes means the yarn composed of fluorescence dyeing fiber and and other colorful fiber. In recent years, Colored spun yarn is becoming more and more popular because of its hazy appearance and energy-saving production process. Now in China,the colored spinning industry is developing fast, colored spun yarn containing fluorescent dyes is one of the main features. Fluorescent dyes have been widely used in textiles for many years, but the theoretical study on color matching of fabric containing fluorescent dyes is not mature and there is no color matching method aimed at colored spun yarn containing fluorescent dyes. In the production of colored spun yarn the color is matched by repeatedly proofing,so it has long production period and low production efficiency. Aim at above problems, the color matching method for colored spun yarn containing fluorescent dyes was studied in this paper.Firstly,the study was focused on the the optical properties of the fluorescent dyes in order to give useful information to the color matching of colored spun yarn containing fluorescent dyes. The absorption spectra、excitation spectra and emission spectra of fluorescent whitening agent VBL was measured and analysed to get the relationship of them, then a conclusion was obtained that the fluorescence quantum efficiency does not change with absorption wavelength of fluorescent dyes, but the only changes with the emission wavelength.Secondly,three methods for blends of pre-colored fiber including Stern-Noechel model、 Friele model and double constant Kubelka-Munk model were studied. It was found that the double constant Kubelka-Munk model was the best method for color matching of melange fibers. The relative error of the reflectivity predicted by double constant Kubelka-Munk model was less than5%.Finally,the James S.Bonham s K-M theory used for color matching of fluorescent fabric was analysed and then improved through combining with the two constant K-M model, the reflectivity formula of colored spun yarn containing fluorescent dyes was achieved. The fluorescence quantum efficiency of the fluorescent fiber was calculated by the formula and it was used as the basic data together with the relative absorption coefficient (K) and scattering coefficient (S) calculated by the least square method to get the reflectivity of colored spun yarn containing fluorescent dyes. The calculated reflectivity was compared with the measured one. The results showed that:the method could be appropriate for predicting the reflectivity of most colored spun yarn samples (less than10%relative error of reflectivity), but the error would be larger (60%relative error)with the reducing of fluorescent fiber in the sample because the parameter SM/Sf was not calculated correctly and the absorbing ability of the fluorescent fiber in the blended fibers was not represented accurately.In a word, This paper mainly studies the color matching model of colored spun yarn containing fluorescent dyes to further perfect its color theory, and it has important practical significance to develop new product and promote the automation of color spinning industry.